1. Field of the Invention
The present invention relates to a color photographic light-sensitive material and, more particularly, it relates to preventing fading of the dye images ultimately obtained by development processing a color photographic light-sensitive material and preventing discoloration of uncolored areas (hereinafter referred to as white background).
2. Description of the Prior Art
Color photographic light-sensitive materials are, in general, prepared by coating on an appropriate support a silver halide emulsion containing couplers dispersed therein. Conventional color photographic light-sensitive materials are produced by dispersing couplers capable of forming cyan, magenta and yellow dyes upon coupling with the oxidation products of color developing agents into red-sensitive, green-sensitive and blue-sensitive silver halide emulsions, respectively, and coating these emulsions in an appropriate order on a support.
Color photographic light-sensitive materials thus produced are subjected, after exposure, to a series of processing steps such as color development, bleaching, fixing, stabilizing, etc., to ultimately form color images.
Recently, an intensification process in which color dye images having the same optical density are formed, but using several tenths of the amount of silver halide present in an ordinary light-sensitive material, has been developed. A cobalt (III) complex salt and a peroxide are known as intensifying agents. In such a processing, silver images and color dye images are formed in a color development step just as in a conventional process and dyes are further formed in a subsequent intensifying bath by the reaction of a coupler with a color developing agent, which is present in the photographic material, oxidized with an intensifying agent in the presence of image-wise distributed silver as a catalyst. After bleaching and fixing steps, the dye images remaining in the photographic material comprise azomethine dyes or indoaniline dyes. Therefore, the color images thus-obtained are in substance the same as color images formed in a conventional manner.
Color photographic images thus-obtained are stored for a long period of time as records or to be displayed. However, these photographic images are not necessarily stable to light, humidity or heat and, when exposed to light for a long period of time, the dye images tend to fade or discolor and, in addition, the white background is also discolored, usually resulting in a deterioration of image quality. Such a phenomenon is enhanced when the dye images are exposed to light or stored under high temperature and high humidity conditions.
This fading and discoloration of images are fatal defects in a recording material. The following compounds have heretofore been used to remove these defects. For example, hydroquinone derivatives including 2,5-di-tert-butylhydroquinone, phenol compounds such as 2,6-di-tert-butyl-p-cresol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-isopropylidenediphenol, etc., and tocopherols are representative of such compounds.
These compounds are effective to some extent as an agent which prevents fading or discoloration of dye images. However, the effect is not completely satisfactory or, although some compounds may prevent fading, they deteriorate the hue, cause fog, reduce dispersion property or form crystals. Thus, satisfactory color image stabilizers which exhibit completely excellent effects for photographic use are not known.
Methods for improving these disadvantages are disclosed in Japanese Patent Application (OPI) No. 14023/1976 and U.S. Pat. No. 3,930,866, in which a phenolic compound as described in U.S. Pat. Nos. 3,432,300, 3,573,050, 3,574,627 and 3,930,866, British Pat. No. 1,347,556 is used together with a hydroquinone derivative. However, even with these somewhat improved methods, the prevention of fading or discoloration of dye images and the stability of the dispersion are still insufficient. Further, most of the hydroquinone derivatives used in the above described methods have the disadvantages that two to four reaction steps are required for their preparation, that a high reaction temperature or a long reaction time is necessary when a few reaction steps are involved and that the dispersion containing the hydroquinone derivatives per se has insufficient stability, etc.